Synthetic biology aims to endow living cells with new functions by incorporating functional gene networks into them. By overexpressing, blocking and rewiring native gene pathways, synthetic biologists have harnessed this promising technology to reprogram cells to perform diverse tasks such as drug discovery, biopharmaceutical manufacturing, gene therapy and tissue engineering, etc. In this review, we focus on current technologies of synthetic biosensors for disease detection. We start with the design principle of synthetic biosensors. Then we move towards the characteristics of simple synthetic biosensors, which can respond to a single input signal, and complex synthetic biosensors including Boolean gate biosensors, cascade biosensors, time-delay biosensors, oscillator biosensors and hysteretic biosensors, which can respond to more than two input signals and perform complex tasks. Synthetic biosensor has showed great potential in disease detection, but it is still in its infancy stage. More efforts should be made in identifying and constructing clinically relevant regulation systems. Computational tools are also needed in the design process in order to guarantee the precision of the synthetic biosensor. The ultimate goal of a synthetic biosensor is to act as a therapeutic sensor-effector device that connects diagnostic input with therapeutic output and therefore provides all-in-one diagnostic and therapeutic solutions for future gene- and cell-based therapies.
Biosensing Techniques ; methods ; Humans ; Synthetic Biology ; methods

An enzyme electrode biosensor was used for the amperometric determination of inosine in its tablets by co-immobilizing nucleoside phosporylase and xanthine oxidase on a hydrogen peroxide electrode. As a fundamental electrode the hydrogen peroxide electrode has an advantage of stability in analysis compared with the 02 electrode. The enzyme electrode showed a linear response to inosine in the range of 1-268 mg/L with a response of 60 seconds under a sample injection volume of 25 microL. Based on the enzyme electrode, inosine solutions were determined with an average recover rate of 100.8% and a relative standard deviation (RSD) of les than 0.14% in 20 assays. The lifetime of the enzyme electrode was relative long and could be used continuously at 25 degrees C for 25 days. These results demonstrated that the enzyme electrode biosensor could be used to determine inosine and its derivatives specifically, rapidly, conveniently and economically.
Biosensing Techniques ; methods ; Inosine ; analysis ; Sensitivity and Specificity

The self-made high sensitivity and selectivity micro-biosensor was applied to monitor the change of dopamine in cerebral nucleus in rats in vivo. The micro-biosensor was prepared and used to detect dopamine level in vitro and monitor the dynamic change of dopamine in different cerebral nucleus in vivo. The results showed the lowest concentration of dopamine that could be detected by the biosensor was 32.5 nmol/L. Its positive peak was significantly different from that of AA, 5-HTP and E. The biosensor could keep working for monitoring the dopamine concentration in the cerebral tissue for more than 10 h. It was concluded that the microsensor has high sensitivity and selectivity to dopamine and can be used to dynamically monitor the change of dopamine in vivo.
Biosensing Techniques/*instrumentation ; Biosensing Techniques/methods ; Brain Chemistry ; Corpus Striatum/*metabolism ; Dopamine/*analysis ; Microelectrodes ; Monitoring, Physiologic

A protein microarray biosensor based on imaging ellipsometry has been developed as a high-throughput and fast technique for protein analysis. As an automatic technique, it has advanced properties such as label-free, multi-protein simultaneous detection, static or kinetic analysis for protein interaction, and qualitative or quantitative analysis. It has been used for the biomedical applications including tumor markers detection, hepatitis B test, protein competitive adsorption and kinetic visualization for protein interactions. It have demonstrated promising potential for further applications in biomedicine.
Biosensing Techniques ; methods ; trends ; Humans ; Protein Array Analysis ; methods ; trends

OBJECTIVETo improve the key technology of immunesensors in immobilizing bio-sensitive element and keeping its bioactivity, an enzyme immunosensor based on chitosan-SiO(2) (CS-Sio(2)) hybrid membrane was fabricated. To estimate the new immunosensor Vibrio parahaemolyticus which was the main pathogens of aquatic products.

METHODSA CS-SiO(2) hybrid membrane was prepared using sol-gel method. The enzyme immunosensor was fabricated by coating the membrane and horseradish peroxidase labeled Vibrio parahaemolyticus antibody (HRP-anti-VP) on the surface of four-channel screen-printed carbon electrode. The immunosensor was characterized by cyclic voltammetry. Vibrio parahaemolyticus could be detected according to the decrease percentage (DP) of peak current before and after immune response, while cyclic voltammetry was used as an electrochemical mean to detect the products of the enzymatic reaction. Seven kinds of bacteria, like Vibrio alginolyticus, were selected for specific experiments.

RESULTSBy studying the infrared spectrum of three kinds of films, the CS-SiO(2) hybrid membrane was prepared and HRP-anti-VP was fixed in the hybrid membrane. Under the optimum conditions of immunoreaction and electrochemical detection, the DP of peak current before and after immune response showed a linear relation with lgC in the range of 10(4) - 10(9) cfu/ml, while the linear regression equation was: DP = 6.5 lgC-3.319, the correlation coefficient was 0.9958 and the detection limit was 6.9 x 10(3) cfu/ml (S/N = 3). The immunosensor possessed acceptable specificity, reproducibility (RSD < 6%), stability (the amperometric response was 95% of the initial response after a week) and accuracy (96.7% of the results obtained by the immunosensor were in agreement with those obtained by GB/T 4789.7-2003).

CONCLUSIONThe enzyme immunosensor based on CS-SiO(2) hybrid membrane gave a good performance in rapid detection of Vibrio parahaemolyticus.

Biosensing Techniques ; instrumentation ; methods ; Electrochemical Techniques ; instrumentation ; methods ; Equipment Design ; Immunoenzyme Techniques ; instrumentation ; methods ; Silicon Dioxide ; Vibrio parahaemolyticus ; isolation & purification

This paper introduces the new research achievement and progress of electro-physiology in olfaction and gustation. Classical implements such as patch-clamp or glass pipette are not appropriate in the dynamic detection of cellular signal transportation. In view of this, we have analyzed the feasibilities and challenges of olfactory or gustatory cell-based biosensors such as field effect transistor (FET) and light addressable potentiometric sensor (LAPS). Finally we present the research work carried our in out lab and a future prospective on the development in this field.
Biosensing Techniques ; instrumentation ; methods ; Electrophysiology ; methods ; Humans ; Microchip Analytical Procedures ; methods ; Smell ; physiology ; Taste ; physiology

This article summarizes biological detection techniques based on magnetic signal of magnetic nanoparticles and the research progress of these techniques in biomedicine. Biological detection based on magnetic nanoparticles is faster, more accurate and more convenient compared to traditional optical techniques and causes much attention. It can be classified into giant magneto resistive biosensor (GMR), magnetic relaxation switch (based on T2 relaxation time), AC susceptibility (based on Brownian relaxation) and magnetic lateral flow immunoassay. These techniques can be combined with nanotechnology, microfluidics, immunoassay and bio-chips and have wide application prospects in clinical diagnosis, biological detection, environmental monitoring and food security areas.
Biosensing Techniques ; instrumentation ; methods ; Immunoassay ; instrumentation ; methods ; Magnetic Phenomena ; Nanoparticles ; chemistry ; Nanotechnology ; instrumentation ; Point-of-Care Systems

Aptamers are oligo-nucleotides which are selected by SELEX (systematic evolution of ligands by exponential enrichment) in vitro, it can bind protein or other small molecules with high specificity and affinity. Researches on aptamers have achieved much progress in biosensor, drug development and nano technology. This article has reviewed the researches and applications of aptamers in the past two years.
Animals ; Aptamers, Nucleotide ; isolation & purification ; Biosensing Techniques ; methods ; Drug Design ; Humans ; Nanotechnology ; methods ; SELEX Aptamer Technique

Fiber-optic biosensor is now becoming a new research direction in biosensors. In recent 10 years it has got a compelling development and has been applied to medical pathogens, food toxicity, water pollution, biochemical weapons, fast detection for environmental samples, etc. In this paper its development is given out in detail.
Biosensing Techniques ; instrumentation ; methods ; Equipment Design ; Fiber Optic Technology ; Humans ; Immunoassay ; instrumentation ; methods ; Optical Fibers

To develop a specific, rapid and convenient method based on molecular motor biosensor to detect food-borne rotavirus. A specific probe was encompassed the conservative region of rotavirus's VP7 segment, and a molecular motor detect device was constructed by connecting probes to F0F1-ATPase molecular motor through biotin-streptavidin system. This biosensor's sensitivity was 0.005 ng/mL for rotavirus RNA. Extracted virus RNA was conjugated with the biosensor separately, at the same time ATP was synthesized. By comparing fluorescence intensity, we can detect rotavirus RNA in samples. This method possessed specificity for rotavirus, without any cross-reaction with Hepatitis A virus and noroviris, and it could be accomplished within 1 h. We detected 15 samples using this method and the results were compared with RT-PCR results. This method is sensitive and specific for rotavirus, and it can be used to detect food-borne rotavirus.
Biosensing Techniques ; methods ; DNA, Viral ; analysis ; genetics ; Food Microbiology ; methods ; Rotavirus ; genetics ; isolation & purification ; Sensitivity and Specificity